Classifier



oct. 16, 192.4

F. w. MACLENNAN 1,977,195

CLASSIFIER Filed Feb. ,5, 1951' 4 Sheng-sheet 1 BY/r/'s ATTORNEYS 0d. 16, 1934. i F Wl MACLENNAN 1,977,195

GLASSIFIER Filed Feb. 5, 1951 4shets-sheet 2f oct. 16, 1934. F, w MACLENNAN 1,977,195

CLASSIFIER LFiled Feb. 5, 1951 4 Sheets-Sheet 5 Oct. 16, 1934.

F. w. MACLENNAN 1,977,195

CLASSIFIER Filed Feb. 5, 1931 4 Sheets-Sheet 4 INVENTOR 'i Fran/r W Nac/ennuh.

BYh/'S ATTORNEYS 'fl particles therein.

33.9.' places of storage or treatment.

Arares trice CLASSIFIER Frank W. Maclcnnan, Miami, Ariz.

Application February 5, 193i, Serial No. 513,581

12 Claims.

This invention relates to classifiers and more particularly to means for the removal thercfro of the materials separated thereby. 'In my co-pending application, Serial No. 17, 1929, now Patent 1,895,468, I have disclosed an improved form' of classifier'wherein solids are removed from a slime pulp in separate grades according to the diiierent v specific gravities and degrees of neness of the In the prior application, the invention is shown as, applied in a classier of a conventional'type consisting of a relatively shallow tank, of large horizontal area and with a slightly inverted conical bottom, and provided with a central feed well; an outer peripheralr overflow launder and a revolving rake arm mechanism adapted to move the settled solids gradually toward the center of the tank, and the removal of the solids in incre- '2 ments of different nneness as produced by the sorting action of the classiiier is effected by providing a Vplurality of annular troughs spaced at suitable distances from the well and the launder ahdconnecting these troughs with lead-oit conduits so that as the settled solids are moved toward the center of the tank theyv are collected in the troughs and moved along these troughs by Scrapers operating therein to the lead-off conduits whence they are withdrawn to suitable The present invention is a further adaption or development oi the principle of the prior application and makes it possible to apply such prineiple' to existing installations with a minimum of alteration and shut-down. At the same time greater liexibility` of Voperation is permitted because of the adjustability of the parts. The presentinvention has the further advantage that it makes'it possible to elect the removal of the settled solids at dierent points as desired without providing a set of underground'or otherwise relatively inaccessible conduits.

laccording to the present invention, the settled solids are removed by one or more, usually a-plurality, of pumps the intake means for which are so arranged as to travel in spaced annular paths, and 'usually 'in annular troughs, dened upcnor in thelbottoin of the tank,v toward which the settled solids are movedV by the revolving rake i' mechanism in the normal operation oi the classier. These pumps are advantageously carried upon the revolving rake supporting Yarm and means is' provided lfor' vertically and radially adjustingl'tne pumps and their associated intake and discharge conduits so as to permit the settled material to be taken from the tank at any distance from the center.

The hereinbefore mentioned and other advantages of my invention will more fully appear from the following detailed description when taken in VView of the drawings and will be more particularly brought out in the claims.

In the drawings Fig. 1 is a somewhat diagrammatical plan View of the device;

Fig. 2 is an enlarged detail plan View of parts of the construction shown in Fig. 1;

Fig. 3- is a vertical sectional View of the tank showing the radial arm in position below the bridge;

Fig. 4 is an enlarged vertical sectional View taken on line 4 4 of Fig. 2;

Fig. 5 is a horizontalsectional view on line 5 5 of Fig. 4; v

Fig. 6 is a detail view partly in section of certain of the parts shown in Fig. 4 locking inthe direction of the arrow;

Fig. 7 is a plan view similar to that shown in Fig. 2 but illustrating a modification;

Fig. 8 is a view similar to that shown in Fig. 3 but illustrating a modification of Fig. 7; and

Fig. 9 is vertical detail View of the suction box and its supporting conduit looking in the direction of the arrow in Fig. '7.' i

Referring to the drawings more in detail, wherein the same numerals represent the same elements throughout, the tank l0, annular launder l2, central feed well la, feed launder i6 suported by a stationary bridge 17, trough 18, the rake arm 22 bearing on a suitable support 28, and Scrapers 24 are substantially the saine as those heretofore employed in classiers of this type. As in my earlier application above-mentioned, additional annular troughs are spaced at suitable distances from one another and from the trough 18 on the one hand and from the periphery of the tank on the other. For convenience in adapting the invention to an existing installation, and as well for convenience in adjusting the grades of the sorted material that is to be collected in and drawn from each trough, these intermediate troughs may be formed in a layer 26 of loose material such as sand and other settled solids that is added to or allowed to accumulate upon the bottom of the tank to a sufficient depth. If this is done, it will, of course, be necessary to raise the rake arm and scraper mechanism sufficiently to insure that the Scrapers will operate at the new bottom level. in a new installation it will ordinarily be as convenient to form the i the troughs in the settled solids.

lar launders 36 positioned adjacent the outer end f of the arm. Instead of leading to peripherally arranged launders, the conduits 34 may discharge the material into a discharge conduit placed at the center of the tank or into any other suitably placed launder o-r conduit.

Connected to the inlet of each pump 32 by means of a connecting member 38 is a vertically arranged conduit which extends downwardly toward the bottom of the tank 10. Each conduit 40 is advantageously made stream-line shaped inv cross section at the lower end, as sho-wn in Fig. 5, 'so as to prevent undue agitation of the slimes and is adjustably attached to the side of the box 30 by a suitable strap 42 so that it may be adjusted vertically relatively thereto and to the bottom of the tank 10.

Each conduit 40 is open at its lower end and has attached adjacent thereto a horizontally-extending suction box 44, having a top 39, side walls 41 and 43, bottom walls 45 and 47, and a back wall 49 at one end and being open at the other or front end, to which are attached Scrapers 46 which extend outwardly and upwardly from opposite sides thereof diagonally in the direction of movement of the conduit. The front edges of the bottom walls constitute cutting edges to cut Also, by having the box 44 open at the front end only, the dilute material which ows into the trough in back-of the box is not drawn up through pipe 4Q by the pump and only the thickest pulp is yso withdrawn from the trough. In each box 30 is provided means 48 for actuating the pump therein. EachV box 30 has a laterally extending flange 50 on each side through which bolts 52 areadapted to be passed to detachably secure the box to the By means of this construction, the boxes may be detached from the arm and moved to otherl positions along the length thereof from the positions shown in the drawings whereby the pumps may withdraw slime from any annular E region of the tank desired. For convenience in adjusting the position of the pumps and their enclosing boxes, the conduits 34 may be made of suitable flexible material. Similarly, the connectingk member or conduit 38 will ordinarily be flexible to permit of easy adjustment vof, the

pipe 4D.

Also the Scrapers 24 are made adjustable so that their inclination relative to the arms, as well as their distances from the bottom of the tank,

may be adjusted as desired particularly when the bers may be provided as may be deemed necessary to properly support the conduits.

In the operation of the apparatus a liquid pulp is fed through the feed launder 16 into the feed well 14 where it passes out into the tank` i 19V slowly flowingV outwardly towards the outer edge thereof. As the pulp flows through the tank the heaviest and coarsest grained particles settle to the bottom near the center, the lightest and nest particles settle out near to the outer edge, and the intermediate sized particles settle out in the intermediate regions of the tank with a gradual gradation from relatively coarse to fine toward the outer edge. The rake arms carrying the Scrapers and the pumps rotate slowly around a bearing at the center ofthe tank. `The scrapers carry the settled materials or slimes in the various annular portions of the tank towards the annular troughs therein. The suction boxes 44 travel in these troughs and the pumps connected thereto pump the slimes out therethrough. It is understood that the pumps, suction boxes 44 and Scrapers 46 form and maintain the troughs 20 in the layer 26 of loose material on the bottom of the tank.

By having the boxes 30 adjustable radially along the rake arm, they may be positioned to permit the pumps to remove the slime from any annular trough or from any annular portion of the tank desired. vWhen the troughs are defined in Aa bottom layer-of loose material it becomes a Very simple matter to form a new troughto meet any adjustment desired. These features give the apparatus greaterv flexibility of operationv and make it possible to eect a high degree of. selectivity in the removal ofthe slimes in accordance with the neness and specic gravity of the particles therein.

Itwill be understood that, when applying the invention to an existing installation, the usual lead-oiT conduits 56 such asv shown in Figs. 7 and 8, which have heretofore been employed tov withdraw all ofthe solids as they are moved to the centrally disposed trough 18, need not be closed up if Vit is more convenient to continue to use` them for withdrawing that portion of the solids that will be collected in the central trough 18 in the normal operation of the classifier according to my invention. In this-way, a partof the solids,-v that part collecting on the outer annular portions of the lbottom of the tank,-will be removedv by the overhead pumps and the rest will be removed through the lead-off conduits 56 asin the practice heretofore followed.

By having the boxes 30 substantially wholly immersed in the pulp, sufficient clearance roombetween them and the stationary bridge 17 supporting the feed launder 16 is provided for the pumping equipment to pass under such bridge. Because of the slowness. with ywhich the arms rotate and the distance above the bottom ofthe tank at which the boxes are placed, they will not agitate the slimes to any objectionable degree.

By having the conduits 40 adjustable vertically the suction boxes thereon may be positioned adjacent the bottom of the tank regardless of the radial position of the boxes 30. The Scrapers 46 act to crowd the slimes toward the openings to the suction boxes 44 so that the material being pumped out will be highly concentrated.

Figures 7,8 and 9 show a modication of the device as heretofore described. In this modication, it will be noted that the general construction of the tank, the stationary bridge, and the rake arms are substantially the same as in that modification shown in Figures 1 to 6 inclusive, except, however, that the peripheral launders 36 have been omitted but the overflow launder 12 retained. Also, in; this modiiicationy shown in Figures 7, 8 and 9, `only a single overhead pump is used to remove material from thebottom of the tank and the usual conduits 56 .are provided to remove the material from the central-trough18.

In this modification, the suction box160 `s mounted on the end of the conduit .62 which extends upwardly and forwardly at an angle to the vertical. The upper end of'conduit .62 is pivotally connected `to conduit 64,' through the joint 68. The conduit 64 issupportedxbythe framework mounted onl the arm 2211forwardly thereof in the direction of rotation-of the-.arm so that the suction box will lie forwardlyof the Scrapers 24. Supported on the framework 7031s mounted a winch '12 to whichis'attached one end" of a cable 74, the other end of nwhich lis'attached to the suction box 60. The positionof thersuction box relative to the bottom l-offthel tank may be readily adjusted 'by means `of the winch and cable and, if desired, maybe lifted above the-surface of the liquid in-the' tank so-that it .may-be cleaned of chips or other material-which `have caused a clogging` thereof.u Also by having the conduit 62 pivoted and extending downwardly and rearwardly from its pivot the suction box will be enabled to ride over any obstruction lying in the bottom of the tank which it may meet. Furthermore by positioning the suction box in front of the arm and the Scrapers in the direction of rotation, the material being drawn up from the bottom of the tank through such box will not be diluted due to any stirring action of the arm and the Scrapers 24.

The conduit 64 is connected to the inlet of the pump 76 support-ed in a box 78 similar to the boxes 3G heretofore described. The pump 76 is operated by a motor 80 and has a conduit 82 connected to its discharge outlet. The conduit 82 extends along the arm 22 and enters the side Wall of an annular sump 84. This sump 84 is formed by placing an annular partition 86 inwardly of the outer wall of the central rotating feed well 14 mounted on the arm 22 and by leaving the bottom of the feed well between the walls unperforated while leaving the central bottom portion of the well perforated as usual.

A pump 88 mounted on the stationary bridge 17 and operated by a motor 90 also mounted on the stationary bridge has a conduit 92 extending into said sump to adjacent the bottom thereof for withdrawing material therefrom. A conduit 94. leads from the discharge end of this pump 88 along the stationary bridge 17 to any suitable receptacle for receiving the thickened solids.

While the modification of Figures 7, 8 and 9 is shown and described with only a single suction box to withdraw material from only a single annular portion of the tank, it is obvious that a plurality of such suction boxes may be provided for operating in a plurality of spaced annular troughs so that pulp may be withdrawn from a plurality of annular portions to the tank. Instead of providing a separate pump box for each suction, it is only necessary to install a single ptunp box at one position and operate all of the suction boxes therefrom through suitable connections and pumping means.

While I have disclosed a means for advantageously practicing my invention, it will be understood that such disclosure is illustrative only and that various changes may be made in the construction and operation thereof within the scope of my invention as pointed out in the appended claims.

l. In a classifier, a settling tank, a feed-well, a plurality of spaced troughs formed in the bottom of the tank at progressively greater distances from the feed-well, scrapers' 'movablyf supported inisaidftankntomove material collecting on `the bottom-.ofsaidtanktOsaid troughs and pumping means movable along said troughs for sepa,`

rately. removing material from the said troughs.

2-111 a classifier, a settling tank, spaced annular. troughs formed in the bottoni of the tank, an army rotatably supported centrally of the tank, andvmeanssupported by said arm for separately pumping material fromeach of said troughs..L

:In aclassien a settling. tank, a plurality of spaced annular troughs formed in the bottom ofthe tank, a rake arm rotatablymounted on said tank landcarrying scrapers adapted to move ma-` terial collecting-.on the bottom of theltank vto said i troughs, land means .for separately removing material fromithe` said troughs including pumpingmeans supported bysaid rake arm."

Inl au'classiiier,` a settling tank, a `rotating arm? mounted 'centrally yof the tank, pumping means mountedon? the Varm and adapted to1 remove separately material collecting on different portions of the bottom of the tank, and means mounted on said arm for moving material along the bottom of the tank into the paths of said pumping means.

5. In a classifier, a settling tank, a layer of loose material on thev bottom of the tank, means for forming and maintaining a trough in the loose material, Scrapers mounted to move over the surface of said layer, so as to move material collecting thereon to said trough, and pumping means supported above the bottom of said tank for removing material from said trough.

6. In a classifier, a settling tank, a central feed well, a layer of loose material on the bottom of the tank, means for forming and maintaining an annular trough in the loose material in spaced relation to the periphery and to the central feed well, a rotatably mounted rake mechanism for moving material collecting on such layer to said trough, and means for removing material from said trough.

7. In a classifier, a settling tank, a layer of loose material on the bottom of the tank, means for forming and maintaining an annular trough in the loose material, a rake arm rotatably mounted centrally of said tank, rakes carried by said arm and adapted during rotation thereof to move material collecting on such layer to said trough and pumping means supported by said rake arm for removing material from said trough.

8. In a classifier, va circular settling tank, a layer of loose material on the bottom of the tank, spaced annular troughs formed in the said layer, rake arms rotatably mounted centrally of said tank, scrapers mounted on said rake arms directing the slimes in the bottom of the tank toward the troughs therein, pumps carried by one of said rake arms and adjustable longitudinally thereof, launders for separately receiving the material passing through said pumps, discharge conduits leading from said pumps to said launders,

and vertically adjustable intake conduits opening into said troughs and connected to said pumps.

9. In a olassier, a circular settling tank, a stationary bridge supported on top of said tank and extending from the center to the periphery thereof, an annular sump adjacent the center of said tank, an arm rotatably supported in said tank centrally thereof, pumping means supported by said arm withdrawing material from an annular portion of the bottom of said tank intermediate the center and the periphery thereof and discharging said material into said sump, and other pumping means'r supported by said stationary bridge for withdrawing material' from said sump. 10. In a classier comprising a settling tank, an annular trough formed inthe bottom. of. said tank, an arm supported for rotation about the center of the tank', andV scrapingk means carried on said varm for directing solids settling fromv a slime pulp on to the bottom ofy theY tank toward the trough therein; means supported by said armV so as to move in said trough in advance of said scraping means forremoving a. layer of settled solids from said trough. 11. In aclassiiier comprising asettling tank, an annular trough formed in thebottom of said tank, an armsupported for rotation about the center of the tank, and scraping means carried on said arm for directing solids settling from a slime pulp on to the bottom of the tanktoward the trough therein; a conduit supported by said arm, a suction box supported by said conduit so as to move in said trough in advance of said scraping means for 'removing-a ayer ofi settled solids ,from said trough, and means .connected with said conduitfor withdrawing material from said trough through saidbox to said conduit.

i 12'. In a classifier comprising a settling tank, an annulartrough formed in the bottom of said tank, an arm supported for rotation about the center of` the tank, and scraping means carried on said arm for directing solids settling irom a slime pulp on to the bottom of the, tank toward the trough therein; a conduit pivota11y-support-- ed by'saidarm, asuction `box supportedby said conduit so as to movein said trough in advance of said scraping means for removing a vlayer of settled solids from said trough, means connected y with said conduit for withdrawing material'from said trough Vthrough said box and said conduit, and means supported by said arm for turning the conduit about itsipivot to raise said box above the surface of the material in said tank,

e `FRANK W. MACLENNAN.

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